RO
SR EN ISO 6145-6:2009
Gas analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 6: Critical orifices (ISO 6145-6:2003)
ISO 6145-6:2003 specifies a method for the continuous production of calibration gas mixtures, containing two or more components, from pure gases or other gas mixtures by use of critical orifice systems. By selection of appropriate combinations of orifices and with the use of pure gases, the volume fraction of the calibration component in the calibration gas mixture can be varied by a factor of 104. Additionally, it can be changed by a factor of 102 by changing the initial pressures in the orifice systems. The uncertainty of the method depends mainly upon the flow calibration method and the variations in temperature and outlet pressure. The relative expanded uncertainty in the volume fraction obtainable for a binary mixture (at a coverage factor of 2) is 3 %. If pre-mixed gases are used instead of pure gases, much lower volume fractions can be obtained. The mass flow rates or volume flow rates, from which the mass or volume fractions are determined, can be calculated and can be independently measured by a suitable method given in ISO 6145-1. The merits of the method are that mu
Status :
Withdrawn
Approval date : 1/30/2009
Publish date : 2/1/2009
Withdrawal date : 2/28/2018
Number of pages : 18
ICS : 71.040.40 Chemical analysis
Technical Committee : 357 - Natural gas
- Normative reference SR EN ISO 6145-1:2009
- Normative reference SR EN ISO 6143:2007
- Replaced by SR EN ISO 6145-6:2018